Hey Coop,
You might be onto something. I have another 1954 D quarter I used as a comparison. Both coins have the exact same diameter so to your diagram it seems less likely to be an acid thinned coin.
In the rim comparison images the coin in question is on the right. It does appear to be slightly thinner than the normal 1954 D quarter especially in some areas of the coin. That said, the coin is only .15 g underweight which looks like it's still within the mint's tolerance. I know striking pressure can also impact the rim width so I'm still a little unsure if it's a rolled thin planchet, a weak strike, or a combination of the two. I'm leaning toward a weak strike but I will defer to the experts.


