From Carl Von Hoffman's book, "Jerry on Safari". He was the cinematographer for the trip. If I'm reading the gun list right, they took:
1- Holland and Holland double rifle in 600 Nitro
1- Winchester 1895 in 405 Win.
3- Hoffman Arms Co. rifles in 375 H&H (including Col. Waldon's rifle).
4- Colt New Service revolvers (Col. Waldon's was at auction not long ago)
From T. Murray Smith's book "Safari Trail". The "Waldon Expedition from Cairo to Cape" was his first job as a PH. He omits Col. Waldon for some reason, probably writing from memory i would guess. He also can only remember Carl Von Hoffman's first name.