Is this oil pump shot?

I need to put an oil pump into der Scheisswagen.  To recap, the engine failed when it failed to lubricate the #2 rod bearing and sent bits of it all over.  the old oil pump looks like this inside:

I'm assuming that the grooves and nicks are going to be a problem in the long term and I should have something that is smooth.  So I ordered up a replacement OEM used unit from a recycler.  That one looks like this:

In both cases the impellers have some shiny wear spots, but no indications of nicks, grooves, or anything like that.

Since most of these die from lubrication problems, I wanted to be sure that the replacement pump wasn't FOD-Ed but it looks like this ingested some things too.  I've always heard that the only thing that really kills oil pumps is ingesting metal, so I'd like to avoid that situation, of course.  A brand new Merc unit is about $600, and a Febi unit is about $250-$300.

So, am I right in thinking that both of these pumps are not to be trusted?  Or do they need a lot more damage to be considered a problem?

All oil pumps ingest some schmutz, as it is before the filter.

If there is no deep scoring, I'd run it.  I assume Mercedes does not offer tolerances to measure, so you can't get all feelery with it.

Febi probably made it for Mercedes, though, and that doesn't seem horribly expensive.

Is this a gear pump?  What do the bores look like where the smaller ends of the gears go? 

The gears should not be touching those walls in normal operation.  Your main concerns as far as wear would be any grooves on those faces that span from the inlet to the outlet (or almost all the way).  This creates a leak path reducing flow and thus pressure.

If they are not FOD'd out, gear pumps usually wear away the bores/bearings that support the gear ends (the gears are constantly trying to push themselves apart).  If they wear enough you end up with gears that start to touch those outside walls, which creates FOD.

You're likely correct - I think Febi is the actual manufacturer that Mercedes buys from.  There are a number of new oil pumps for sale on eBay for around $150, but I ain't touching those.

I also haven't been able to find any specs anywhere to try to measure anything.  It seems like the replacement that I got has less chipping on the edge, so maybe it's a better choice.

It is a gear pump and I didn't look too closely at the walls, but I don't recall seeing anything that jumped out at me.  I may go back over to the shop later today so I can take another look.

At this point, if I've got to spend it, I'll spend it, but I don't want to go off and replace something that's got another 100k miles in it just because it isn't perfect.  Mercedes already tried a "The Best or Nothing" approach, and it didn't work out too well for them, so I'm trying the "It's not just good, it's good enough" approach.