These may help

Non-rebounding Early .577, 1876 note the position of the hammers/strikers

I borrowed this pic from the previous post, 3dogMike, I hope you do not mind, shows similar hammer position

Rebounding, .450/400 X 3 1/4" late 1880's

Rebounding, H&H 8 bore Ball gun 1887

Rebounding, .577 3" late 1880s early 1890s

Rebounding, WR Cape rifle 577/450 + 12g 1901 (very surprised at this late date)

Rebounding lock hammers are usually clear of the strikers

TH44