is there a markings on 16mm films as to who put them out?

[Jim Schrader]

do any 16mm films have markings on the leaders that suggests who put them out?

[Maurice Leakey]

MGM 16mm prints usually have details marked regarding processing by MGM labs.
Technicolor print leaders will contain a lot of information.
But, generally, 16mm leaders do not contain information of the distributor, the leaders will be standard 35mm SMPTE leaders which will also contain the film's title.