I have 11 of them, including three ersatz ones with screw driver/bottle openers differently shaped from the originals. Yours has a differently shaped sd/cl, so probably not a Trio by Trim. Three of mine have Trim stamped on the handle, three have trim-trio, one has oxford chemicals, and one has nothing. The 8 are tang-stamped with Bassett/Derry CT/Made in USA or Bassett/USA/Patented pat #. Also a two-digit number like 72 or 96.
Two of the ersatz are tang-stamped usa in fine print on the sd/cl, one is totally unmarked.
More than you asked, but I'm guessing yours was USA-made, too. Though just because I've never seen a foreign made one around here doesn't mean they don't exist elsewhere. Or even here, come to that.
I just noticed the ersatzes don't have the separate key-chain hole.