Odd Brown AE40 Base ring & set model # question

[RotoTech99]

Dear Forum:

I've encountered an unusual brown color AE base ring... I obtained it through Phoneco as compensation for an earlier lost new base ring.

Please answer this question, has any CRPF Member encountered one like this before?

Also, I have a question regarding what the base model number might be... It has the D-68640A with the condenser with. 4mF for talk/dialing, and. 7mF for ringing, coded EC on it.The lead wires are small cloth covered ones, not the larger ones as in earlier AE40's.

The baseplate is discolored, and I cannot discern/see a model # on it.

The hookswitch blocks are chrome without a bar between them, and the hook plungers are chrome. The handset is the Type 41 with regular black caps.  The ringer is a D-56515A SL ringer rated. 4mF.

I've read on CRPF that most likely a "41" series AE40 set, would be equipped with smaller cloth coated or plastic wires, and high impedance ringers. and that AE40 sets coded "40" were equipped with low impedance ringers, and the larger cloth jacket lead wires.

I know it's unlikely, but can anyone please speculate what the appropriate model number might be?

I've also included a picture of the gold label showing the patent and "D-" code, with the last letter or digit missing.

It does have the "Chicago 7" address code as well.

All replies, and feedback acknowledged with Thanks. Merry Christmas

RotoTech99