Gene, a few notes:
I asked about the D&T'd because the earliest 99 I've seen that has the odd D&T holes is a 1934 R (no others till 1936).
The 99-H that ctw referenced is one of 3 that I have in my 99-H data, all made 1936. This is of a sample size of 1934,12 ea; 1935, 14 ea; 1936, 19 ea and 1937, 13 ea. I also have one from 1938.
I had a Spiegel set up with Lyman blocks and a Lyman 438 scope using the odd D&T holes at Rick's Savage Fest. Lyman made a rear block that was designed to be mounted where the back two holes are located. It has allowance for the cocked indicator which it mounts over.
The earliest roll engraved rifle I have data on was shipped 11/1936. The major group of roll engraved rifles are from 1938, 1939 and 1940. I have a few non-roll engraved 99's in the 1938 data but non in the 1939 0r 1940 data.
