Cap Badge of U-558 or U-955: real or not?

[IJSBEER]

I've recently met a German seller who (I had previously told him I was interested in Cap Badges) replied back to me the day after I had bought something else from him, and he asked me my email address to send some pictures of a certain cap badge he had, running in his family. And this is what he sent me:

The U-boot insignia stands for the German saying "Holzauge, sei wachsam!". The "Turm Maling" of both the U-558 and U-955 featured this emblem. Not sure if "...sam!..." was washed away by the weather conditions on the original u-boat conning tower. My gut instinct says this is real but what do you think? And how much should I pay for it at max?

Edited November 5, 2016 by IJSBEER