Thanks again
I remembered I had William Larkin's books and according to him the Expeditionary Force in China was
VF-3M which changed name to VF-10M on 1 July 1927, had 9 x FB-1 (Sep 1927)
VO-10M no previous designation listed, had 6 O2B-1 and 6 OL-6 (Sep 1927)
Looking back in the USMC section (Feb 1926), he lists only four units.
First Aviation Group
Second Aviation Group
Observation Squadron Two
Scouting Squadron One
I cannot see he lists any VO-5M at all.
Was this a very temporary designation which existed for a very short time before becoming VO-10M?
Finally, the Curtiss which crashed at Pensacola still has no unit.
Larkin does not list Pensacola as USMC base at all....
Cheers
Stig