The wheelchair graphic was introduced on the 1977 base starting at H1000.
1977-1978H1000 - H3???
1977 BASEGeorge Kunsman
1979-1991H3??? - H9999
H/A 1000 - H/F 9999
The 1979 base continued the previous numbering, starting between H2994 and H4007. After reaching H9999, it switched to 1000H.
After 9999H, a stacked prefix was used, starting at H/A 1000.
SPECIAL PROTOTYPE "NJ" 0000