Curtis,
I hate to burst your bubble, but as you know I have lived with Eureka for some 15 years on a daily basis. There is no one more familiar with her workings. Believe me, when I say a part is the original, I say so because I have already checked. If there were any question about the rods being the original, I would not have said it. So, get out your trusty eraser and change the file on this item. Stamped on each rod,toward the rearmost end on the bottom just before it goes into the "D" strap is Eureka's number: 8-18C-18. Likewise this number is on every course of the boiler, as well as all the valve linkage, including the nuts and bolts. The damn number is everywhere.
You may have missed seeing the numbers because this is in an area that catches a lot of oil and dirt during operation. But they are there.
I appreciate your interest in the authenticity of the various components that make up the locomotive. In fact I went through the same search you did when I cleaned every single part myself on the old gal. I wanted to make certain myself of what was original and what may have been replaced.
Talk to ya later!
Dan