Serial number in the inside of the left dropout, "drilled" vent holes only in the loop, nice Western style letters in the brake bridge, Exp TT length 18"-18 1/2", Pro TT length 19 1/2", Exp-Pro TT O.D. 1", Exp-Pro DT O.D. 1 3/8". (Pics of a 1984 Pro Star but the Pro Racer frames are the same!)

Serial number in the inside of the left dropout, "drilled" vent holes only in the loop, nice Western style letters in the brake bridge, TT length 19 1/2", TT O.D. 1", DT O.D. 1 3/8". The chainstays are welded a little lower on the seattube then the TT.

Serial number in the inside of the left dropout with a "baseball" logo at the end. Drilled ventholes in the loop. Same nice Western style letters on the brakebridge like on the US frames. Japanese forks are made by Tange and there is Tange engraved in the steering tube. Also, there is a little venthole at the end of the fork legs.Thanks to Arno from France.

Serial number in the inside of the left dropout, same place like the US frames but different font. "Drilled" vent holes in the loop and behind the seattube. Western style letters in the brake bridge but again a little different then the US frames. "Keyhole" slot in seat tube (seat tube is 5mm longer above the TT then the US ones). Dropouts are rounded at the end of the slots. Fork has a little different designed dropouts. Welds are not clean! Size and measurments are the same like my 1984 US Pro Racer. Propably a Taiwanese frame,  because those vent holes behind the seattube.

This frame set has the same details like the unknown Pro Racer above. Serial number in the inside of the left dropout, same place like the US frames but different font. "Drilled" vent holes in the loop and behind the seattube. Western style letters in the brake bridge but again a little different then the US frames. Dropouts are rounded at the end of the slots. Fork has a little different designed dropouts and the dropouts have inside a different place of weld. Propably a Taiwanese frame,  because those vent holes behind the seattube. This frameset was bought orginaly in 1987.

Serial number on the BB, 4 "stamped out" vent holes in the rear end ( in the loop and behind the seat tube), rounded style letters on the brake bridge, 19 1/2" TT length, 1" TT O.D., 1 3/8" DT O.D., Later style red/blue decals. Made in taiwan. Thanks to Singlespeed Kent.

Serial number on the BB (as for I know starting with M4-…), 6 "stamped out" vent holes in the rear end (in the loop, behind BB, behind the seat tube), rounded style letters on the brake bridge, 18 1/4" TT length, 1 1/8" TT O.D., 1 1/4 DT O.D. Made in Taiwan.

Early Hutchins models (89?-90) had a serial number on the left dropout from Japanese  leftovers. Later models didn't have a serial number.
"Drilled" vent hole only in the loop. Blanc brake bridge. Ovalized top tube at the seat tube connection. 20 1/2" TT length, 1 1/2" DT O.D., 1 1/4" TT O.D. Made in USA.