I'm working on the first part of a serial number check.
This first part errors out with an 'CRC' error, so I'm assuming
this is a CRC check.

The serial is 16 characters with the 5th and 6th being letters.
Some type of CRC is calculated with the first 14 and checked
against the last 2. Here is a small list where the last 2 are valid.

0000A B00000 000 51
1000A B00000 000 30
1111A B11111 111 50
1234A B12345 123 61
1111A B22222 333 51
1212A B12121 121 45
9999A B99999 999 45

Is this some type of CRC check ?
Could someone point me in the right direction...

Thanks !

Yes: Reverse the application and analyze the algorithm to find the answer to your question. With the limited information you've provided, no one could help you even if they wanted to.