What did 'make love' mean in the '60s?

• It had the first meaning in that context;
• it could have the second meaning in other contexts;
• in yet other contexts it was useful to leave it ambiguous;
• it's pretty much always meant both those things, so No; although this context undoubtedly confounded, deliberately, eros and agape;
• I don't remember any other meanings, but we were mostly pretty drugged up at the time.

As recently as 1967, a soul singer Ronny Dyson had a hit with these lines in its title and refrain:

If you let me make love to you,
Then why can’t I touch you?

Although I’m certainly no expert on the euphemism making love meaning having sex, if you read any British literature from the 19ᵗʰ century, you find a lot of instances of phrases like her lovers and he made love to me and I want to make love to thee, and so on.

Given how the prevailing social mores of the Victorian era have come to make its very name a byword for prudence, it’s a good bet that phrases like those from that period are not a reference to fornication or sex. It’s more like a man courting a woman, asking her to marry him, and then the sex begins.

Although written by a late 19ᵗʰ and early 20ᵗʰ century writer, Lady Chatterley’s Lover is filled with sex. But I never read it. I did see the stupid and poorly produced (circa 1980s) porno movie based on it. It was written by DH Lawrence.

In one sense, the term making love is just a euphemism for having sex. During the "free love" movement of the 60s, "Make Love Not War" was a concise way to embrace promiscuity and protest the Vietnam War at the same time. So much progressive counterculture wrapped up in just four monosyllabic words – it doesn't get much more efficient than that!

In another sense, though, making love has a more literal meaning, referring to the strengthening feelings of closeness that often accompany acts of intimacy. The theist might refer to this as the spiritual dimension of sex, while the evolutionist might describe it as a cocktail of dopamine and endorphins. Explain it however you'd like, the point is, amidst a swirling blend of vulnerability and trust, two people often feel a rush of heightened closeness, a feeling of intimate bonding. During sex, they are "making love," that is, they are creating the feelings that often accompany emotional love and infatuation.

One blogger explained it like this:

I’m talking about the reason they call it “making love.” This is the erotic pleasure that is given and received as an expression of the commitment, passion and friendship you share with that guy that stood at the altar with you. Of course you may not be “feeling it,” before you begin – but opening yourself to such joy makes both of you feel better about yourselves. Not only that, but those delightful orgasms flood your bodies with oxytocin, the bonding hormone. You literally feel closer to your mate, richer, sexier and more valuable.

Another website reads:

It is not a cute phrase for sex, but having deeper meaning. Sex is the physical act, regardless of the context or emotions of the persons involved.

Making Love, is just that – creating love. The act, when done with love between the persons involved, brings up the deepest feelings of love they have for each other.

All that said, sometimes the term is stripped bare of that deeper meaning, and it's merely used as a euphemism for cheap sex. As Tammy Wynette crooned:

A little barroom, on his way home
A bed to lay on in a room upstairs
What's her name, he'll never see her again
Close the door, who knows, who cares

And they call it makin' love
Makin' love, makin' love
Throw it down, pick it up
Dress it up and call it love

Together alone like nothing's wrong
In a house called home, in a double bed
They've grown so far apart, they just fumble in the dark
Not one single word is said

And they call it makin' love
Makin' love, makin' love
Throw it down, pick it up
Dress it up and call it love

Incidentally, OED indicates that using the expression "make love" to refer to sexual intercourse dates back to 1622, so the phrase has probably meant most all of your suggestions at one time or another.