Hi Brian,
I drove out one of the roll pins and installed the Slingerland pin. A perfect fit, except for the slightly longer length.
Here's what I found; the Ludwig roll pin is 1/8" x 5/8". The Slingerland roll pin is 1/8" x 3/4" (1/8" longer).
I found the 1/8" x 5/8" roll pin on eBay from companies that will also ship to Canada. A quick example is item number 172851939565
-Mark