I've been out of the habit of packing my lunch for a few weeks but when I do it's usually chicken salad or roast beef and horseradish sauce on a wheat thin bun, fruit or veggies, and water.
I would have to say that the LCP is just too damn small for his hands. The subject on grip and finger placement is a very opinionated subject. We could discuss this all day but there would be no way for me to steer the thinking of a firearms master (like yourself) in a direction towards a different path.
.22
Slide would have had the "Ace" inside a diamond on both sides of the slide.
Left side would have said "Colt Service Model .22 Long Rifle"
Here's an example of one on gunbroker.com
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=255035109
I believe the frame was produced in 1980 based off of similar models serial range at the time around when you say it was shipped. Also found a few questions in my search of people asking value and production date of guns with close serials to yours.
There is no reason a lowered dually cannot be used to pull a 5th wheel as long as the suspension is properly set up. A good friend of mine built a bagged and bodydropped dually on 22.5's and he hauled multiple 5th wheels in the time that he had it.