I think some of them came without heaters, that was considered luxury in some cars. A hardy lot they must have been.
I would suspect that this stuff would also seal internal leaks to a degree, so it might be of benefit to keep in the system.
Dave, let us know when you know. Sounds like a busy trip. I will certainly have some housings ready by that time. They weigh in at about 1300 g each. But I presume you will have your kit stuffed with cheap wine, biltong and god knows what.