If you Google
up a sister ship will know whether a rub rail is the norm - the only reason why she never had one would be if homebuilt / finished. To my mind that does look like an "out of sight out of mind" job (for something meant to be hidden) and if not removed by the vendor probably removed by another PO - if no screw / bolt holes (now filled?) then rub rail might have been glued on - which may explain why it is no longer there (docking collision(s!) or simply hull
I would carefully price
up the cost of fitting a rub rail (whether yard or DIY) - it won't be a 5 minute job
.....nor under a $100's - if it was, the Vendor would have sorted it......and reflect that within the price
(in comparison to another vessel that has a rub rail already fitted).
Looks like the Rub rail would have been an L shape - which probably explains why no replacement was fitted - as would be an awkward one to fit to hull shape.