[Milsurplus] Obscured BC-348 tag ?

[Hue Miller]

I found in my accumulation a nameplate for a BC-348-P,  date WF-42.
Oddly, the serial number field of the tag is covered by "something".
Whether it's a super hard paint, or some ancient duct-tape like thing
....no, wait, I took my glasses off and up-closed it. It looks eradicated.
Grinding wheel or wire brush grooves all running vertical.
I mention this because I believe in the past we'd discussed eradicated
S/N on Navy A/C equipment, I think RUGF?

Certainly was not a thorough effort, considering the small number of
nameplates thus processed. I doubt the S/Ns would have given 
Japanese mathematicians much useful information. Altho it's true,
later in the war, S/Ns off German tanks were exploited by the Allies
for some kind of production estimates.
-Hue Miller