Hey, I'm not cheap! I'm thrifty. But thanks, anyway.
I discovered this by opening it to put in a new roll, so the 1st 3 shots are ruined. A check of the shutter and aperture settings suggests it's either PANF or FP4. So, I'll just shoot remaining 9 at 100. That's a good idea about stuffing the box end into the accessory shoe, if your camera has one. This Compur shutter doesn't even have a flash sync.
Refer to the sentence that I bolded above. If you are sure that it is either Pan F or FP4, then it would make more sense to expose it at 50 ASA. That'll be fine for either of those films.
I've done this so often that I now use Avery (or any other brand) Removable multi-use labels. They don't leave adhesive on the camera and you can put the film type on almost any surface without damaging it. I usually put it on the bottom plate. 1000 5/8"X7/8" labels are cheap, just a few $. Good luck with the film. Now if I would only set my ISO before metering.
There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks. —Erwin Schrödinger