Looking for Injector service group 3S-6638 or 5m-2788. Need 2x. Or Nozzles 2S442

Morning,

Had the good fortune to find 2 new old stock oem CAT 3S-6638 earlier this week, still need 2 more for my D311H generator set. I believe these were also used on the D320A and a few others.

Available from the local Cat dealer for $89/each - was hoping someone may have some laying around they're not using I could buy for less. I found the two NOS ones for about $25/ each which I don't suspect I'll be as lucky on the next two, but figured I'd ask. If I don't find any NOS in next few days, I'll just order new. I don't want to pollute the machine with chinesium. 

5m-2788 is the original part # that has now been superceded by 3S-6638. I don't think there are any significant differences in them, or reason I couldn't mix/match them. 

I would be open to NOS nozzles alone - without the o-rings in the kit form, as I found enough o-rings in my father's old stash to make do, if I had two more new nozzles. Nozzle part #s by themselves I believe would be 2S4442.

I'll post some pictures and info about the old gen set at a later time after I get a few things done to it - thanks for the help!

Seems to be lots of nozzles out there. I didn't check for service group numbers.
https://www.machinerytrader.com/parts/search?PartNumber=2S4442&SearchType=Start
 

Thanks for that - I will check in with a few of those there. Never thought to look on machinery trader for individual parts and part #s. Have had good luck with ebay in the past but it wasn't turning any more up for now.