The first Torker frame was called the Torker MX in 1977 pictured below.

Yes, the MX frames have the serial number stamped on the BB and notice the forward facing rear dropouts. These were designed for larger riders like Kevin McNeal and had the nick name of "Big Bike or Big Boy"

In 1978 they droped the pressed forward dropouts for welded rear dropouts that are on all Torker models up to the new '83 Pro-X's. The headtube sticker was Yellow with Red lettering then changed to Red with Yellow lettering but kept the Torker MX logo the whole time. 1977 - 1978 the down tube decal had a lightning bolt through it like the Eddy King below which seemed weird at the time since this was a 1980 bike and had an older sticker.
1978 introduced the LP, low profile, frame that suited expert sized riders like Eddy King. They later added the LPX for taller riders which had an extra inch on the TT.

The TorkFlyte and MaxFlytes had different components to offer a complete bike at an affordable introductory price or an Expert level price.
LPX pictured below

1981 they finally came out with a mini for Jason Jensen, thinner tubing, smaller geometry, and mini forks with traditional stickers.

Later the 280 and 280-X models were the most popular complete bikes sold by Torker.
1984 Torker went bankrupt
JT