I have an old Titanium bike that was once listed as a Marin Team Titanium on ebay (in 2004) From research it looks to me more like a Litespeed Standard Mountain Frame from 90/91. The machined finish on the rear drop out (unusual?), two holes and placement / shape of the four digit frame number...
Reviving this post: @GearlessinSeattle Did you ever get your Litespeed frame confirmed as a 1990 or 1991?
Mine has the same machined finish on the rear drop out, stamped framenumber and by the numbers a similar production date.
Thx