i would look and just try not to mess it up too much, better to know if your other gerbil is there and needs to be searched for or not.
mom to Tristan my rescue and new girl, Sierra, RIP Saphira and Sophie, may you both be together forever in heaven, I miss you more than you'd ever know. RIP Theo, I miss you my sweet boy. RIP Kirby, you were a great buddy.
I wouldn't worry about it too much, as long as you know your cage if safe and secure they should still be in there! Especially since it's only been a day, I'm sure you'll see them later on or maybe even the next day. If you don't see them out within a couple days then that's when you should begin to worry.
If you're wanting to check right now, then what I like to do is lightly (not loud) tap on the glass and start talking to wake them up and they'll come to the surface to see what's going on.