Costa Rica Stamp-Op And Cancel-Need Help

Good morning,

I have spent a lot of time trying to "decode" everything on this stamp, its OPs and cancellation, but cannot find all the reference info. I need. Therefore, I am turning to all of you for your expertise. Any help will be greatly appreciated (600 res. scans included). My questions are:

1.why is the word "TIMBRE" covered up (TIMBRE meaning "official") and then in the cancellation it says "Oficial 1"?

2.Is there more than one kind of "Oficial" cancellation in Costa Rica, such as "Oficial 2" etc."

3.why was the OP made on it of "Correos de Costa Rica" when we already know it was a stamp from the Republic of Costa Rica?

4.why did they add the OP of "AEREO"? Did they have separate stamps for mail that would be transported on the ground?

5.What other words are in that cancellation as I cannot make them out and cannot find reference material.

Thank you.

This was a regular 20 cent postage stamp that was overprinted for use as an a 50 cent airmail stamp. The first airmail stamps for many countries are regular postage stamps overprinted for that purpose.

thanks for the info. I am hoping the other questions will be answered also. I don't know why this stamp intrigues me, but it does. :)

This was a regular 20 cent postage stamp that was overprinted for use as an a 50 cent airmail stamp. The first airmail stamps for many countries are regular postage stamps overprinted for that purpose.

I can see the date "6 ABR 1967", that's April 6th 1967. And the word "oficial".

I believe it is a revenue stamp. Anyone have Scott cataloge where they can look it up? It will be an hour or so before I can.

Scott Catalog C 433 issued 1966

Regardless if it is Revenue or not the overprint mails it an air mail stamp!

No argument from me! Catalog states "Revenue Stamps (basic type of A124) Surcharged.

Hopefully someone knowledgeable of Costa Rica stamps can provide a detailed explanation.

I need to remember to check back on my questions. Thank you everyone for the input. It seems I can always find another stamp to distract me and keep me from coming back. Thanks again :)