That's the low end heatsink for low powered CPUs. The 2 white squares on the MB behind the heatsink are the sockets where the 2nd CPU riser would go, and it's missing the shroud that directs air through the heatsink and down onto the RAM.
Here is the manual, you can see what the complete machine is supposed to look like.
https://downloads.dell.com/manuals/all-products/esuprt_desktop/esuprt_dell_precision_workstation/precision-t7500_service manual_en-us.pdf?dgc=SM&cid=54597&lid=spr1143390441&linkId=44419264
U402F is the heatpipe cooler for the T7500. you can shop for a better price if you like.
https://www.serversupply.com/ACCESSORIES/HEATSINK/PRECISION/DELL/U402F.htm
Some people list the smaller U016F as fitting the T7500, but it's for the smaller T3500/5500 models.
Vendors with the heatsink may have the shroud also.
For the older games that will run you don'y need a 2nd CPU.
The almost 3.9GHz turbo speed of the X5687 would serve you well.
https://www.ebay.com/itm/Intel-Xeon-X5687-3-6GHz-Quad-Core-AT80614005919AB-Processor/132762711932?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=226724&meid=30382a9e870845a9b9bfc4529b9976ac&pid=100005&rk=4&rkt=12&mehot=ag&sd=124113827198&itm=132762711932&pmt=1&noa=0&pg=2047675&algv=SimplAMLv5PairwiseWebWithDarwoV1&brand=Intel&_trksid=p2047675.c100005.m1851
The T7500 CPU riser has 6 RAM slots, . H236F is the correct one. Not cheap. hard to find the complete assy. with both fans and shrouds for under $100 USD.
https://www.amazon.com/H236F-Precision-T7500-Secondary-Board/dp/B014VUB1HU/ref=sr_1_8?dchild=1&m=A3307Y790PRDJ6&marketplaceID=ATVPDKIKX0DER&qid=1589456832&refinements=p_4😀ell&s=merchant-items&sr=1-8
The W715F is the T5500 version with 3 RAM slots and can be found for less.
The 2nd CPU riser sockets have been known to malfunction. I wouldn't bother. Safer to buy a known working machine if you need that capacity.