Reefers and LTL Service

There is evidence that Refrigerator Cars were used in LTL service. Recently, I believe the SV found markings inside the Reefer that was purchased from the S&S which showed placement for LTL material along the way. The locations were, as I recall, between Alamosa and Durango.
I have three questions.
First, is there evidence of short Reefers used for this purpose, or were all used in this manner the newer and more modern long Reefers?
Secondly, is there evidence of Reefers in LTL service after the Passenger modernization campaign of the late 30's?
My guess is that these cars were used in LTL service before the time of the "Modern" San Juan and Shavano, when the number of available Baggage cars for this service may have been fewer because of more service around the system.
My third question deals with a Union issue pertaining to discontinuing LTL service on Passenger Trains. When was this practice discontinued? I'm sure I have heard Bob Richardson speak of this, which reduced revenue at a time the San Juan was being considered for abandonment, which obviously eliminated many Union jobs.