The winding tab and the strip that the operation of the key would remove are both still there. The only other way to get into the tin *might* be to use a rotary can opener - I've never tried that, but the damage it would cause is not present either.
I've used needle nosed pliers to open them. Odd that no can opener ever employed the selling feature of a slot to do so.
No apologies, I appreciate everyone taking a look. The tab is impossible to see in the photo I posted. My fault, didn't know what I was looking for. It is there, but in the dark section. Anyway, now has a 2nd bid. So advertising piece afterall? Probably more valuable than an empty (used) tin which is good!
The tab is clearly visible here. This is totally undisturbed . I am sure this is a display piece that there woulld be no point in opening. I don't think youd want to leave a full tin in sunny shop window for months.