The Lawrence number 18 pocket holster was in their line for many years. The earliest Lawrence catalog I own is dated 1938:
"No. 18 Pocket Holster. For revolvers & automatics.Seams lockstitched.Loop for belt.Tan leather,unless otherwise ordered......$2.35".
Latest catalog I have with this holster listed is # 110,dated 1969.It doesn't appear in catalog # 114,dated 1972.
It was designed to be worn in the hip or front pocket & could be anchored by running your belt through the loop.Usually supplied in unoiled finish.
I would imagine yours was made for a Browning .9 m/m High Power as I don't know of a "BRN .8 m/m" handgun.
Regards,
turnerriver

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turnerriver