99SVT666,
Your plan should work ok. You'll get the windage tray improvements but you will be missing out on the baffling updates. I would advise getting a new oil pan gasket. Assuming you have a 99SVT, yours is 5 years old.
The bolts you have listed look right. The old windage tray was held down with 6mm nuts. The new tray with new studs also requires four 8mm nuts. PN is W701582-S309.
