You may have the upgraded gear. I think it was 2002 and later that got the upgrade but I could be wrong. The tangs were "beefed up". The part number I ordered was SPD-4WM09-29-00 for right around $50.
Here's the gauge setup. https://www.youtube.com/watch?v=0WmxwBpea3M
I found the 0-100psi Marshall fluid-filled pressure gauge on ebay for $20... and got the 10mm banjo fitting and the 10mm x 1.25 dual-banjo bolt from Amazon. But you can find them all over. Saw them on several websites.