Looking for M1 carbine variants

Many m1 carbine manufacturers subcontract to other organizations to make the receivers and other parts. I am specifically looking for these sub variants. I have included a picture of an example from Underwood. They would punch a letter below the serial number. This particular one has a T for Intertype corp.

Let me know what you have! I am a collector and I will pay a fair price!

- IBM M1 Carbine subcontracted with Auto Ordinance with "AO" below SN

- National Postal meter purchased receivers from Underwood & IBM and lined them out and put an "N" between the maker & SN

- National postal meter purchased receivers from Inland and stamped "N" below SN

- Rock-Ola m1 carbine purchased inland receivers, lined out Inland Div. Rock-Ola marked below serial number

- Underwood M1 Carbine subcontracted "T" Intertype corp marked below SN

- Underwood m1 Carbine subcontracted "S" United Shoe Machinery Company marked below SN

- Underwood m1 carbine purchased Inland receiver, Inland Div lined out and "U" stamped above

- Winchester purchased underwood receivers, lined out Underwood and marked "AW" or "WA" below SN