Disc due to lack of consumer interest.
SIG now offers history letters on their website. Lack of sales.
100-500 depending on specifics
Remington's website has what you are looking for.
Let a gunsmith do it.
The Mk IV 380 is a Colt Government Model .380 caliber compact semi-automatic pistol with many of the features of the time tested Government Model .45.
M38
Which model?
Can't be answered without knowing who made it.
Yes, that would be the Model 51 made in 380 and 32 auto.
1920
about 1935
the model 1908 hammerless 380 with serial # 60093 was made about 1923