Question can i downgrade from 4.4 to 4.3?

hi fellow xdaers,

got a question on my i9505. i have installed this rom for a while and due to my local telco running only 4.3, they mention that my phone is grey unit and they do not want to warranty it.

i'm wondering if i can re-flash back to its original 4.3 (telco) rom using odin without issue so that i can bring have it repair under warranty.

any gotchas should i look out for?

thank in advance.
Current: LG G3 D855K 16G

Prev Phone:
HTC One M8, Xperia T2 Ultra (D5303), Note 2 N7105, Note N7000, SGS, HTC Desire, HD2, iPhone