Remington New Model Army

[Hunter-Swede1963]

Hello everyone! Greetings from Scandinavia! I am interested in purchasing a Remington New Model Army, civil war era that hasn't had too many parts replaced with newer ones. The one I am interested in was manufactured in February 1864 with the number #54812. The same serial number appears on the barrel, frame, and trigger guard. It also has faint markings on the left side of the stock. What bothers me is that the hammer seems to have been replaced with a newer model? In the picture, you can see #54812 compared with another revolver, and it has a different pattern on the hammer than #54812. The metal on the hammer of #54812 also looks newer. I think it seems like the hammer is of a later manufacture and not from the same time period. Or is it just heavily polished?
The triggerguard is also heavily polished or is it of later manufacturing?
What do you think?