Your the man to ask on this Paul. I have a steel deck early 90s Victa with a sound deck but with small surface bubbles covering the deck under the original paint, like a rash. I took to part of it with a wire brush but was not able to eliminate all the bumps under the paint. Would you just do the best possible and put up with an imperfect but improved surface and mask off what you can, or go to the trouble of stripping the deck of components so it can be done thoroughly, including a wire brush attachment with an angle grinder and phosphoric acid (rust converter) before paint? I already have a pressure pack can of Indian red to go on.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!