I agree.
The plate looks exactly like one available from Chevs of the 40s that says it is for 1940-45 and '46 cabriolets here:
And as you point out, the rivets are a dead giveaway that at least the original plate has been removed.
That leaves the conclusion that the number stamped on the plate came from a title with a mistake printed on it.
So... the best we can surmise is that the O or 0 is supposed to be a C, D, or a G (March, April, or July).
Ole S Olson
Saskatoon, Sask, Canada
1946 DR 3/4 ton stake
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