This is the best that I could do trying to enhance your small image

[Linked Image from photos.smugmug.com]

I agree there appears to be a crolle pattern that has been blued over.

You might remove the FE and put a dab of white vinegar on a soft cloth and rub a small area of the barrel. The 'scrolls' may become more visible.
Please let us know, or better yet post a full size close up of the area.