I have a copy of that 75th anniversary catalog too; it's a treasure trove of information.
Inflation: from the 1920s to now, you will find varying ratios depending on whether you compare food, goods or housing. The range is somwhere between 20:1 and 100:1 depending on the item.
Let's say produced goods are 25-30X more expensive now. That means the list price on the equivalent handgun (a J-frame Centennial) would be somewhere around $750-900, which i think is about where it is. The counter price will be somewhat lower of course, but I bet it was back then, too.