Can players buy Boots from a visiting StreetPass party?

If I put Boots (which permanently add 2 movement spaces to a Unit) in the inventory of someone in my StreetPass party, and then StreetPass with another Fire Emblem player, can that other player then buy the Boots from my party?

No. Here is a link that has a table of items that are not available for sale via StreetPass teams.

Items that cannot be purchased via StreetPass

Sword Missiletainn, Sol, Amatsu, Falchion, Exalted Falchion, Parallel Falchion, Mercurius, Tyrfing, Balmung, Mystletainn, Sol Katti, Ragnell

Lance Luna, Gradivus, Gáe Bolg, Gungnir

Axe Vengeance, Wolf Berg, Hauteclere, Helswath, Armads

Bow Astra, Parthia, Yewfelle, Nidhogg, Double Bow

Tome Valflame, Mjölnir, Excalibur, Forseti, Book of Naga, Goetia

Staff Goddess Staff

Item Naga's Tear, Boots, Bullion (S), Bullion (M), Bullion (L), Supreme Emblem

DLC Dread Scroll, Wedding Bouquet, All Stats +2, Paragon, Iote's Shield, Limit Break, Silver Card, Outrealm Item