Not specific to L99 Caprices, but specific to all 'early' B- & D-bodies ...
IFF you have the ORIGINAL 'early' '94 coolant reservoir, it has provisions for two hoses on top.
By '95, the coolant reservoir only had one hose provision.
Don't remember when new coolant reservoirs with two hose provisions became unavailable, but it happened fairly quickly.
Not the ISSF's most literate SPI decoder, but, based on GU2 / 2.73 (superceded by 2.93 by '95):
axle is the 'smaller' 7.625" axle (what's the RPO for this? Idunno)
rear brakes are the 'smaller' 9.5" diameter drums ('cause I don't recognize those brake RPOs)