Constant prices may provide a way of tracking inflation, which could be important. Current prices may provide a way of comparing variations in price across product categories AND consumer groups. It all depends on what you are trying to find about Gross State Domestic Product - trends? comparisons? contrasts? indicators of development? or what?
For me, with my small knowledge of marco economics, it doesn't matter very much if at all. you are interested by a ratio. The basic principle would be to take the same methodology for revenue and GDP and then compare the ratio in constant prices and the ratio in current prices. Only if you observe a difference, you can try to exp^lain it. But it could be an artefact. More than the inflation rate, what is relevant for revenue comparison over time is the CPI, Consummer Price Index.
If Revenue is in nominal (current price) terms, so should GDP be (in nominal terms at current prices), if the idea is to use the ratio of revenue to GDP.
Depreciation (the difference between Gross and Net) is an artificial construct (like inflation) and not an observed variable (rather it is a derived variable).