Yes, Pachmayer certainly performed upgrades on Model 21's, LC Smiths, Parker guns, and perhaps others. I've seen more Parker up-grades than any other model; but have also seen Model 21's, and John Allen had a Model 21 up-grade in his shop a few years ago that was gorgeous. It was my understanding that most of this work took place in the 1960's; that the customer just sent them their gun and $5K, and Pachmayer turned their utility grade double into an Invincible, A-1 Special, Deluxe, Grand American, or whatever else was ordered. I've seen some that were really nicely done; and others that were hideous, so each piece must be judged on its own merits. There is a very interesting book called "Frank A. Pachmayer, America's Master Gunsmith" that is an interesting read. As I recall it discussed his up-grading business, and also features pics of some of the guns up-graded there. These Pachmayer upgrades seem to be most noted for their stocks; as Frank Pachmayer logged and sawed his own walnut blanks and obtained some fabulous blanks in the process. He then used many of these blanks on the upgrades.
