Looks like you've got a 106, with the hood and dash from a 104, and the rubber seat from a 102. Unless someone's swapped the transmission that serial number tag matches a 1X6/1X7 unit. Very interesting combo, kinda cool nonetheless!
FrankenCub. They are actually fairly common. A guy uses pieces from his favorite models, or just whatever he has left in fair condition, and slaps a tractor together. No worries, though. You liked it enough to bring it home, and every piece of it was made to last.