FC630 single processor filler/drive fillers

I have a second hand FC630 server that shipped to me with no CPUs and two heatsinks. I'm only going to be using it with one CPU, so I'd like to remove the CPU2 heatsink, but the manual shows a filler should be installed if there is no CPU in socket 2. The problem is, I can't seem to find that filler anywhere.

How important is that filler (or running with the heatsink on top of the empty socket) for airflow in a system like the FC630 or M630? In something like a R620/630 or R720/730, I completely understand why the baffles are important - if you have no CPU in socket 2 and no fillers/baffles, there will be a path of less resistance for the air to flow through, possibly preventing proper airflow through CPU 1's heatsink and potentially causing cooling issues. But in a system like the FC630/M630, with CPU2 being right in front of CPU1, a baffle or filler on the CPU2 socket won't really change the airflow all that much - air will still flow from the front of the module to the back.

That being said, is that filler/baffle REALLY needed in these systems (and does it even exist? I have not been able to find a single real picture of such a part anywhere), and if so, would anyone happen to have a part number? Is it something Dell can sell for a reasonable price?

Related, does anyone have a part number for the fillers for the 2.5" drive bays? Of course Dell had to change the fillers and caddies for the FC630 from the Rx10, Rx20 & Rx30's so that they are not interchangeable. And is that also something I might be able to get from Dell for a reasonable price (I haven't seen 2.5" fillers, but there's a seller on ebay selling 1.8" fillers for $46 each - that's nuts for a piece of plastic - you can find actual drive caddies for way less)?