Help On Mexico C212 50c Chiapas, Big Find?

I recently posted that I received a package of stamp stock books from my Father (90). He sent about 800 more stamps in stock books in no special order. I have been pouring through mostly US stamps but about 350 are from all over the world. I have the 2015 scott vol 1 but get info on most foreign stamps from this community, bidstart, and ebay. I was checking and found that some of my Mexico stamps quoted a higher dollar prices. I am wondering if someone can tell me if If the ones I attached are the same kind or am I missing something? I turned the stamps over in light and don't know if there is a watermark or not. Please help get me unexited. Here's the bidstart page an a couple of scans of what I have. Thanks

http://www.bidstart.com/search_resu...ubmitsearch=

1950 Mexico air mail stamp, catalog value 20¢ used, $3.75 for mint, never hinged. Scott #C193 watermark "GOBIERNO MEXICO"

Scott C193 only a few dollars for mint
or C220E which is very common
But C212 lists at several $100s
You need to check the watermark & perforations

The bidstart does not appear to mention the watermark detail - very questionable items

If you don't have the equipment to check watermarks, a local stamp club might be an option.

I really doubt you have 14 C212's

Hi

Download my Mexico table at:
https://app.box.com/s/k0fwchkjg5u11...m2sh59d9w1ko

The listings may help you. For watermarks, go to the library and get a Scott catalog and make a copy of the Mexico watermark page.

If you wish to download the entire StampRefs let me know by e-mail and I'll send you the link.

Jerry B

Thanks all, as usual you are awesome for the info. I am getting familiar with how to investigate for watermarks. I'm buying some ronson lighter fluid too. Still going through stamps sent to me from Dad.