Mike has it pretty well pegged, although the confusion in the SCSW started to do him in. That's been corrected in the 4th Ed. beginning on page 144.
The Improved I frame has 5 screws and preceded the Models of 1953.
And there were no Kit Guns built on the Improved I frame; they jumped from the Post war Transitional I frame right to the NEW I frame of 1953 (larger trig guard and 1/8" longer rd butt grip, also a new sq butt.)
The gun above is a Model of 1953 .22/32 Kit Gun which is built on the NEW I frame of '53 with 4 screws, later 3 screws. Became the Model 34 in June of 1957.
With the Model of 1953, they began their own serial range and no longer shared the 32 I frame serial #s. So the 4 digit # makes it an early example shipped ~ mid 1954.
And it's a superb example, the 2" variety making it especially collectible. With box, tools, and paperwork in that condition selling at auction in the $1000 ball park.
I hope your friend enjoys shooting it and lets you as well. They're very accurate even with the short barrel.