A letter should confirm the original barrel length. Be sure to include
the full serial number, mentioning the * on the butt, and also mention
the <B> under the barrel, and the date stamped on the grip frame.
Clearly ask about the original barrel length.

Its entirely possible that the barrel was shorter, but maybe not.
From the picture, even a 5" would be a tight fit - maybe the original
length was 4". However, your first post mentioned your grandfather
using the gun in ROTC, in maybe 1916 - 1917 ? If so, that is about
13 years after the gun was shipped. I can't imagine your grandfather
carrrying the gun in a holster like that, so perhaps the holster came
years later.

Hopefully a letter will clear this up. By including the date stamped
on the grip frame, the historian may be able to find the service dept.
records. That is somewhat doubtful, but one never knows.

Regards, Mike Priwer