1958 and 1959:

A 10 foot model with a rear door was called the Sportsman, Jr. and a "New design", the 13 foot model called the Sportsman, Sr., included the now famous "Step down interior". His idea for an affordable, lightweight, garagable travel trailer that could be bought by the average homeowner of the time was a success.  They were a hit and the rest is history. Thousands were sold over the   years with the originals being polished aluminum-today lovingly called the Silversides. A rare Scotty, which appears to have been offered only during 1959 and 1960, is the 12' version with a door in the rear instead of on the side.

The above is a picture of the rare Serro Scotty Rear Door model believed to be only built in the years of 1959 and 1960.

1960:

They added a 15 foot model. Floor plans included a front kitchen with a bathroom/closet and large dinette, or substitute a side table rear couch for the commode. And in the ads, an option on the 13 foot was wings ( the trailers wheels cut outs ) attached to the upper rear. These wings were offered until 1961 when John lost a lawsuit with rival Shasta Travel Trailer and could no longer put wings on his Scottys.

1961:

The Sportsman, Jr. was  discontinued but Scotty continues to offered both a 13 and 15 foot silverside models now called the Gaucho and a 15 foot "Front Kitchen" model. In 1962, the 15 foot "Front Kitchen" model was no longer offered.

John opened the Bristow Okla. plant in 1961 and they started making the making of the 13 ft. silverside being built at the Bristow plant.   This is as far west as the Scotty plants go. 
Compliments:   Jerry Freitag

From: The Pittsburgh Press: Date unknown: By Bob Batz Jr.
Title: Hitching Up to a Dream
Subtitle: His Scotty helped launch the boom in RV industry. . .the below quote:

"... Serro himself led a caravan from Irwin to Mexico City, via Bristow, Okla., where he'd built a second factory. What a sight it must have been: Serro and his first wife, Anna, up front in their finned Dodge Imperial, their gleaming Sportsman right behind, and behind that, 60 cars pulling 60 gleaming Sportsmans. "There was 20 in a group," he says, "and they had to be 20 miles apart because we tied up too much traffic" ..."