2 Attachment(s)
It might be... but we need PHOTOS !!!
"there is no crest on the receiver"
Please be definite: do you mean that there never was a crest, or that the area where a crest would usually be has been scrubbed.
The correct answer is important for identification!
As to the circular mark: does it look like this?
https://www.milsurps.com/attachment....55&cid=1&stc=1
Or this?
https://www.milsurps.com/attachment....54&cid=1&stc=1
Once again, a correct answer is important.
And as already mentioned, we need PHOTOS