That's right - the gauge style changed in 1954 (different new styles for Chevrolet trucks and GMC). That was also the year the high pressure Chevrolet 235 and the 261 became available in Chevrolet trucks (GMC 6-cylinder engines were higher pressure already).
The water temp gauge in that "original NOS set" has the mechanical water temp sender but it looks like an electrical sender connection for the oil pressure (which I think GMC might have had with that pre-54-style gauge).
