The bleeding on the back has never a bench mark of telling an original, as lots of repros have some blue on the back edge too. If you know what you're looking for, this sign has a couple red flags. I have this repro posted in the known reproduction section on Old Gas. We don't like to post all the problems here on a public forum due to the fact that the repro scums glean Old Gas and other sites for information on making their fakes better. Anymore, I would avoid any IR54 Mobilfuel offered on Ebay.
FYI, a quick look of completed sales for "Mobilfuel" on Ebay shows 23 results. Of the 23 results, 22 are pump plates. Of the 22 pump plates, 21 are repros!