Hi, Richard...
I don't know what you can see on the source material you've been looking at, but generally speaking, the A-1 and A-5 were very similar externally. You can determine an A-1 because it has the shorter, original length wings, where the aileron forms part of the contour of the wingtip. On the A-5, the wings were similar to the later A-4, in that the ailerons were inset into the wing, and the entire wingtip was exactly that... a wingtip, and did not have any of its contour formed by the aileron.
Hopefully these thumbnails will help you identify the two sub-versions... A-1 on the left, from
www.warbirdphotographs.com, and the other an old, long-past e-bay auction, I believe.
Regards,
Paul