If you mean G05-802 (19") and G05-805 (15"), they are the same deflection PCB, but you need to change two resistors' values (R604 and R704) to use a 19" deflection in a 15" (or vice versa. Details are in the manual, but here is the summary:
802 (19"): R704 = 820 ohms, R604 = 910 ohms
805 (15"): R704 = 750 ohms, R604 = 750 ohms
The HV is the same for both models. (No changes needed.)