(Mini rant)
I'm a fan of finding legitimate First Day / Last Day Postal Card rate usages.
Even o.k. with collector inspired First Day / Last Day Postal Card rates
Like finding cards used after rate increase, either with postage due or passed o.k. without.
Like cards used within their issue period. (before next card / same rate comes out)
These two are none of that. To me they are an abuse of two very nice UX11 & UX15.
The collection they came in was advanced, and the collector seemed to like various first/last cancels.
Dec.31 1962 - Jan.1 1963 does not seen to match any philatelic milestone.
(The collector did seem to be close by the Washington D.C. post office when he needed cards cancelled) Postal employee?
(Mini rant over

)
Can anyone come up with a possible reason to commemorate other than end of year?
Thanks,
pat
