it depends on whether they have been rebarrelled or worked on, of course, but i suspect that the smaller of the "1908" mausers will be chambered for 7 x 57mm. we'd need more detail, butit could possibly be abrazilian commisioned mauser. spain, and parts of south america, used the 7x57 as their military cartridge. germany, however,went for the 8 x 57. so you might have one of each.

there were mausers in 6.5 x 55( swedish), but as far as i know none were built in germany. most came out of Carl Gustaf in sweden, and i don't think they were 1908 models, although i could be wrong.

in any event, i am envious of your good fortune to obtain such a collection. good luck.