Posted 09/03/2016 10:20 am
I did a quick search on the two sites I know of (Wexler's die varieties and Variety Vista) and didn't see any known DDOs for that year for Philly or Denver. (there was one listed for San Francisco 1990-S proof but not on the motto, date and mint mark) But on your coin I see more of an issue with circulation flattening than showing hub doubling on the die that struck your coin. I looked through the series of 50 states and noticed a common thread there. With the single squeeze dies, the only devices shown as a doubling was mainly on the ear area and a few other examples of minor doubling on the reverses. With the single squeeze die process, the die often starts in an incorrect position, then snaps into place leaving a small kiss area then the rest of the devices as normal.
This usually affects the central area of the die (the ear on quarters). (I found nothing affected on the mottos) So we could rule out this area on the single squeeze dies. On the multi-hubbed coins, it happened a lot in that area. The proof die I mentioned earlier had two digits of the date and the mint mark affected. (yes mint marks can show hub doubling because it is part of the design since 1990 forward. But Like I mentioned, I see nothing on your coin that looks like hub doubling.
