The workmanship (or lack of) certainly speaks against it being a Dovo. What does it say on the other side of the tang? I know you don't want to conflate the two issues, but is there any chance of a picture of the razor that you acquired from this site? I only ask because the shop seems pretty emphatic in its judgement that that one's not good and if we could have a look at it it may give us a good clue as to whether their judgement is worth a fig.