I was unable to do so because the letter grades given the coins do not correspond well with the coin's actual grades (as measured by the visible dots on the cheek straps of the helmet of Parthian coins.) With ancient coins, the dies degrade during use and some dies are higher relief than others. So unlike modern coins, which can be graded according to rules like 'number of stars visible', ancient coin grading involves looking at the entire surface of the coin for wear. I do not do that here, focusing only on the cheek strap of the Sinotruces' helmet. The grader of the coins below might have considered other parts of the coin that you don't see.
I could find no coins in Fine or lesser condition on acsearch.info. There are some available elsewhere, but acsearch.info shows only coins good enough to make it into auction catalogs.
Here are most of the Parthian Sellwood 33s on acsearch.info, sorted by grade.
What's important is what we are NOT seeing. There is no more than a weak relationship between the definition of the individual dots and the dealer's chosen grade for the coin.
Because the seller's grades don't seem to line up well with the quality of the cheek strap, it is hard to say if there are better coins for sale or looser grading standers. I cannot therefore make any statistical claims about the true grades of coins being offered for sale. This data should warn buyers looking for a quality specimen to look closely at the photograph rather than trusting a dealer's letter grade.