Dear Periannan Chandrasekaran,
the word guḍi is normally used for 'temple' in the early Telugu inscriptions.
K. M. Sastri (Historical Grammar of Telugu, p. 68) refers to SII X, 709 (kōyilala) but the text has kayilala (~ kavilala 'cows'), so it is probably a misprint.
The inscription that you refer to (e. g. IA 13, pp. 50-55) has peddakōyilamu 'old temple' but it occurs in the delineation of a grant and may hence rather be an individual name.
Apart from that I am not aware of another early inscription that has the words kōyila or kōvela. If I happen to come accross another instance I will let you know.
Best wishes,
Jens