Someone might have substituted a 'found' item for the correct spacer at some point in the past.

The back inner portion of the timing gear and the front edge of the cam bearing are bearing surfaces which rub against that thrust plate/flange. But they don't always look like it - in particular I've seen new gears with fairly rough looking surfaces there. You can get steel thrust plates now which probably won't wear as quickly as brass, although if everything is OK in there the brass should be perfectly adequate.

Some steel gears will make slightly more noise but should last longer. Although with a stock valve train a replacement fiber gear is perfectly capable of lasting as long as the rest of the engine is everything is OK. Make sure that the oil sprayer is working correctly. Once the new gear is on but before putting the cover back on you can crank it around a few times to check it. If it isn't spraying, the gear won't last long.
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I'm JohnMc, and I approved this message.