I've Inherited An Extensive Collection And Feeling A Little Overwhelmed

Control numbers are accounting codes, hence the name. They are not plate numbers. At best, they can exclude plates when you have a reference list of plate numbers used during a control period.

They are especially interesting with Edward VII stamps (1/2d and 1d) as they help identifying the paper and / or printer.

A very nice collection. The British stamps appear to be at GB Concise level with some added varieties (Edward VII controls, George VI cylinder blocks, with controls).

That Jersey overprint on a German stamp, unfortunately, is bogus.

Welcome Kyle! Some nice stamps there, looking forward to more photos.
Regards
DavidR

What makes you say that it's bogus NSK? Is there something you've noticed?

No German stamps overprinted were issued in the Channel Islands. Also, this stamp was issued in 1937. What was it doing on Jersey, in 1944?

British stamps were overprinted for Jersey, but withdrawn after protests. Very few real stamps have ever left the post office.

Oh I see. So the stamp is perfectly real just that somebody has added some decoration, perhaps to celebrate D Day. Great, thank you for reaching out! Learn something new everyday!

Well, they are more or less "British" islands, even if not formally part of Great Britain. So, celebrating D-Day by overprinting a German stamp with swastikas and the word "Jersey" may have been British humour.
Mayby some poor Wehrmacht sod was looking forward to having Eier mit Senfsoße or Handkäse mit Musik.

My money, however, would be on some crook trying to make someone part with his cash. It is the simplest explanation.

Reminds me of the joke about the guy staggering out of the pub, and being sick on a passing dog. "I don't remember eating that!"

Kyle, your post in this community reminds me of my own posts a few years ago as I struggled to learn some basics about stamp collecting.

As others have indicated, your granddad left you some very nice organized material.
If you do have a set of catalogues they would prove priceless as educational materials.
FYI -- I bought most of my own stamp catalogues as used books for sale from libraries that had updated their own references.

Have fun with your newly acquired collection. Don't sweat what you don't know. This forum and perhaps a local stamp collecting club can provide many experienced collectors willing to share their knowledge.