Prices you pay for parts you cant get?

[HK1837]

No. Whenever GMH started to put ADR29 on passenger vehicles the passenger vehicle doors had intrusion bars. Commercials even to the end of WB didn't have intrusion bars. So a HZ passenger door is very different to a HZ commercial one. ADR29 became mandatory on 1/1/77 but GMH as always bought it in slightly earlier but maybe not as HX passenger vehicles appear to have gone to BHX after 12/76 but commercials stayed as AHX until the end of HX.