I worked on the Model 53 survey for a few years before handing it off to Matt, and I would have to concur with Bert (and Matt) that the buttstock is not original. The composite buttplate rather than the original steel one is the most obvious giveaway. With regard to crescent buttstocks on the Model 53, during my time on the Model 53 survey, I came across several of them but was usually able to examine a photo of the fit between the buttstock and the frame. In most cases, the fit was subpar, strongly suggesting that the crescent buttstock was a replacement. In very few cases where the fit is good, it’s still hard to tell, as Bert mentioned. Maybe it is original, or maybe the owner was fortunate to have the replacement crescent stock fit well. In general, if anyone has a chance to acquire a Model 53 with a crescent buttstock, I would recommend carefully examining the fit between the stock and the frame, as well as checking to see if there is visual consistency between the color and wear between the forestock and the buttstock. Personally, I would probably pass on a Model 53 with a crescent buttstock.