yes, u need to run it before any attempt of cDNA synthesis. if RNA is not good or absence, of course your downstream process will not successful at all. my suggestion is, try to run your RNA sample in 1% of AGE at 100volt for 30 minutes. if your RNA is in good condition, you should get double band (or more). that double band represent 18s and 28s (if im not mistaken) RNA which is abundant in any living cell.
your 2nd question: yes, im using the same reverse primer. because my primer were designed with modified nucleotides. thus it is suitable for PCR. but your kit, if it says do not use the same primer, your should use its nested primer. read your manual properly.
i just wanna share one experience with you, my colleague study on goat. she retrieved sample from goat's saliva. NONE RNA/DNA were able to extract from those samples. so, you should reconsidering on how to get RNA. the best is cow's blood of cow's meat. choose which ever suit for your case