New brake rotors; bad to have one be a tiny bit different?

[Figit090]

I recently bought some new OEM replacement rotors through a friend with a small business (saved some cash), and both rears are from the same company but one of the fronts is slightly different from the other. As I understand it they're probably all made in the same factory, but there are noticeable differences:

One looks machined with crosshatching on the braking surface, while the other has directional concentric lines on the braking surface. Not quite as shiny and machined looking.
One has 6th small hole near the stud holes, one doesn't.
One has slightly larger spacing on the vent holes, so less "fins" in the vent portion, if you will.

Same dimensions and they appear to be the same part/type, and he said it won't matter, but I'm one to do things symmetrically so I wanted to check that I won't get asymmetrical braking or very different wear..

I'm not sure I can really send one back anyway....but I still want to check if this is ok.

Assuming I don't have a big problem; there's considerable surface rust, should I have 'em machined to clean and even them up?

 

[suprarx7nut]

I'd be very hesitant to run rotors of any difference. Last thing you want is an unexpected pull to one side in an emergency situation because one rotor is superior to the other and grabs harder.

Material can make a difference, so can cooling design, rotor mass, the location of that mass, ie inertia...etc. I wouldn't run two different rotors any way you go about it. I'd sooner run a cheap $70 pair from the worst brand Autozone carries. Your braking system is the last place to skimp on anything, for your sake and those around you.

My 0.02

 

[Figit090]

Thanks for your opinion, that's pretty much how I feel. They are the cheaper OEM replacements, which I figured would be fine seeing as how it's just my commuter car, I do have some middle-grade pads.

I sent my buddy a message, I just hope I can get them returned or my effort to save money will just cost me time and money.

@#$%

 

[Figit090]

Well, looks like the return would be kinda tricky since the supplier is not a store, it would be a warranty thing.

So I either machine them both or send 'em back and get another pair locally. Probably the same price.

So irritating...