The 2017 Gaming Table list three different Large Crown chips as having a JR monogram, and more than a dozen Small Crown chips, with a JR monogram.

Fortunately, only one LC order used the Mont Clair font, which is what I believe your chips have on them.

Red, Blue and White chips were shipped to J. L. Martin, at 801 S. Tremaine, LA, CA in 1955.

You have a complete set of those chips. I don't think those chips have yet been posted to the ChipGuide.