AP Royal Oak service question

[Belmont]

I have inherited my father's AP Royal Oak. Can anyone help me ID the series and age? Model 4100SA, Case No. B41770-1123. My father was the original owner, but I do not know its service history. I have sent the watch to AP for service and they are proposing to replace the mechanical movement with the "next generation" of similar automatic winding movement. Will this impact the value of the watch? Thank you in advance!