yes, stardust cost per power up increases once every 2 levels.
https://pokemongo.gamepress.gg/power-up-costs
stardust cost alone can tell you within a 1.5 level range what the level of your pokemon is, and if you power it up until the power up cost changes, then you'll know 100% what level it is.
for example if your power up cost is 7000 and you power it up until the power up cost is 8000, that is when you have a level 35 pokemon guaranteed.
