I know what ejector marks are but I have a question.

I’ve seen a number of articles where the advice is to fill them with CA glue - is there an advantage of this over using plastic putty, or is it just an alternative method?

Cheers,

Nigel

It will cure more quickly and be harder.

One thing to be careful about is that if the filling is significantly harder or softer than the surrounding styrene it will be more difficult to get a smooth surface. If the filling is softer it is easy to sand down the filling too much, if the filling is too hard the surrounding plastic will be sanded down before getting the filling to the correct level.
My preferred method is to punch out small styrene discs using a punch-and-die set. Glue a disc or two into the ejector pin hole, let dry and sand down.
/ Robin

I'm with Robin here-- a punch set and styrene discs is the easiest, least messy and best way to do this. Putty is the next best, but as Robin said, CA is the least optimal because you'll be sanding the surrounding plastic before you make a dent in the CA.
VR, Russ