Not sure about A/C prewiring, but a word of caution. There has been considerable discussion in the HTF regarding the quality of Towlites manufactured during the late 90's. Apparently Hi-Lo, to save weight, or cost, built those Towlites with all wood frames in the upper half. Some are now experiencing wood rot issues and therefore lifting problems.
Recommend you search the HTF library and study up on that topic before buying. Somewhere around 2001 Hi-Lo went back to a metal frame in that model line.
1967 17' Hi-Lo Bon Voyage (1967-1969)
1969 19' Hi-Lo Bon Voyage (1969-2011)
2004 27' Hi-Lo TowLite (2010-present)
2015 Chevy Tahoe LTZ