Almost. I just measured a board here. Your 39mm is 36mm. The 25 is ok but when cut from a panel of 2 or 4 would probably be 24mm, depending on cutter blade loss. So that is determined by how you assemble them. Most PnP shops will want to put lots of those in one big panel because they're just too small to do one by one.

edit - important:
Keep in mind that the USB tab is not thick enough for correct insertion. It either needs a thickener as part of the casing/heat sink, or a 2mm board thickness should be used. I believe the USB spec calls for 2mm but often boards are ordered default as 1.6mm.

***

I got the fan working. Turns out all these local *#@$! fans are garbage fakes. They don't actually have a Tach 3rd pin. They just feed back the voltage fed in, which of course is not right for the Tach reader circuit, it applies 12V to the 3.3V circuit when it should be an open collector/drain to GND that pulls down a connected resistor. Did that so many times here I'm lucky something didn't blow. But in the process of figuring this out I also determined that these crap Chinese cheap fans also don't put a Schottky diode in them to prevent back-EMF, which they should have.

So the question arises - should I have a diode on board to protect against connecting a crap fan? The 3 I tried here didn't blow anything but they did unleash about 30V across the FET, which fortunately has it's own built in Schottky diode. Decent CPU fans have a diode in their "hub". One of my fans does have a Tach pin that works and seems to feed back a suitable signal to test with but it's a small 70mm fan that I won't be using except for tests until I buy a real-man's fan. (Which is a bit of a Thai pun... get it?).

BTW my fridge and the small magnifier ring light both cause enough EMI on the power line here to cause a USB disconnect. Probably the source of much random noise. Half the time when the fridge turns on, cgminer re-inits the KLn device. They're on the same outlet circuit.