Yes, IDT can synthesize oligos for 5’RACE. Order as “custom RNA oligos”. RNA bases should be written with a lower case “r” in front of them. If your oligo contains deoxyuridine, use “/ideoxyU/”. For example, the oligo that I ordered was:
(from Turchaninova et al., Nature Protocols 2016)
Also, make sure you select RNase-Free HPLC Purification (available at >=100 nmole scale).