I was working on a few suggestions for this, including labels and stampings but worked through to this possibility. Incidentally, I really like the design. Looks great.

Have the area for the name painted or otherwise colored with the green color that you show. Make sure that the pin is solid metal of decent quality. Bronze, Brass, Nickle Silver or Sterling... Most likely you would be looking at Bronze and Nickle silver for affordability. You could use the bronze (Gold when high polished) for life members or founding members... others of higher esteem and use silver (nickle silver) for regular members. Thinking of the bronze, it could even look nice with the aged patina applied to it.

Anyways, for the printing, color the name plate area and have the information Engraved into it. As the engraving goes through the enamel or whatever you would use it will then expose the color underneath, (Gold or Silver) Then for the Member Number, that can just be engraved into the item.

Or the original thought that I was thinking was having name tags and numbers PRINTED on plastic or stamped into another metal and glued into place.