Check here for the schematics:
http://www.nostalgiaair.org/Resources/239/M0013239.htm
Loops weren't real common yet in '38, from what I've seen. I suspect the original grille cloth would have been similiar to the rest of the '38 Philco line, more of a tan/brown color with some sort of pattern. Go here:
http://www.radiodaze.com/
and look under components, then grille cloth.
Great set, best of luck with it!