That is what I use and you will be fine. C4.1-77 is awful expensive for 4 lousy pages with very little usable info on those pages and the small plastic sample, but what you gonna do?... (especially if they are copy machine copies as mine were when I bought it several years ago. Complained and got my money refunded.)
This might be a little late but after searching the forum for the answer I found the answer I was looking for in FEMA 353
Per FEMA 353 sample 4 is 500 micro-inches.
5.1.3 Cut Surface Roughness
After thermal cutting, the RBS surface shall have a surface roughness of no more than 500
microinches (AWS C4.1-77, sample 4). Grinding of thermally cut edges shall be provided only
as necessary to meet this criteria. Corners between the cut RBS surface and the top and bottom
of the flanges shall be ground to remove sharp edges, but a minimum radius or chamfer is not
required.