Is it a glitch that I have a kill clock on a non strange weapon?
Apparently, it is possible to create Mercenary grade stat clocks, though it requires a lot of trading up. A user in this thread describes how it can be accomplished.
Q: Long story short, I have a factory new killstreak shotgun that I rather like. I got excited when I heard about civilian stat clocks, because I was hoping I could trade up enough civ clocks to get a mercenary stat clock and make my killstreak shotgun strange. I can't seem to find anything about crafting higher-grade stat clocks though. Is it possible to combine civ-grade clocks to make a higher grade clock, or can you only turn civilian-grade weapons strange?
A: I'll try to answer because I've actually done this. Like /u/DerpyPotater said, Stat Clock (SC) civilian grade weapons can be traded up. I traded up 10 SC, Minimal Wear civilian weapons and got one SC MW freelance weapon. Repeat until you've got 10 SC freelance weapons, and trade those up for one SC merc-grade weapon. I used all minimal wear items, and got a minimal wear, stat clock merc-grade. During all of those trade ups, I never got a wear higher OR lower than what I put in. It is also true that you cannot choose which weapon you get in the trade up- it will be from the higher grade, but it will be a random one of those.
I got my weapons and stat clocks from the market, and it cost about $1.30 - $1.40 for one minimal wear, stat clock civilian weapon. Note that if you need 10 for one freelance, and 10 freelance, you need 100 of these stat clock civilian grade weapons. Cost me around $135, but I now have a minimal wear stat clock top shelf knife. So worth it, although I must admit that I was going for the High Roller's medigun.
So, no, it's not a glitch, but it seems like it would take a lot of time and energy (and money) to have created it.