Best answer is "probably." Most of them I've played/owned were 1-5/8" nuts, or a hair wider. None of them were especially thin at the nut, but they seem to not have a ton of flare towards the bridge, in that they're not much deeper or wider towards the heel. I've yet to come across one that was radically different than any other.
Is your M75 the solid body version or the archtop version?
The archtop version would be more alligned with the Starfires. If you have one of the first of the solid body M75's the necks on those are slimmer in depth. I didn't go and measure the width at the nut so I am only referencing the neck thickness.