Byrd Cover... What's It Worth?

I've never really collected (or had interest in collecting) autographs, however, I did come up with this link on Admiral Byrd and the Antarctica Expedition and if you advance to the bottom of the link there is a letter signed by Admiral Byrd.

It seems to me that something's wrong, as either the letter (at the link below) or the covers scanned above show a bogus signature, as the signatures are only two years apart and they seem very different:

http://about.usps.com/who-we-are/po...tarctica.pdf

I'm no signature expert, but here's a side-by-side comparison of the two examples:

wow wt1, when you put those two together its's not even close. I wonder if he ever varied his signature significantly?

You know what? I could be wrong. At first glance I thought that signatures are identical, and therefore were simply printed. However, after a side by side inspection I noticed the difference in signatures. That makes me think that the covers were signed individually. That doesn't mean that they were signed by Byrd himself though.

I'm actually looking at my other cover now, the one signed by Poul Siple http://en.wikipedia.org/wiki/Paul_Siple I can't fined another cover with his signature. See my topic https://goscf.com/t/22474

Hello frIends!

Here are more information regarding the Stamps, covers and cachet!

http://www.south-pole.com/p0000142.htm

Regards,
Rodolfo

Remember that correspondence was/is very often signed by a secretary... the signature on the letter may not be real, either!