Oh dear...
The same thing happened to me not so long back.
If the car is running OEM turbochargers, Garrett turbochargers or HKS turbochargers you definitely should have water cooling lines fitted in order to keep the bearings cool - as they have a hardened plastic ball bearing cage/jacket that need to be kept cool this way.
My GTR, when I bought it, was fitted with HKS 2530's and the water cooling lines weren't present. Reason being after looking into it further was that the car was originally rebuilt and imported with Trust turbochargers, that do not require water cooling lines to keep the bearing assembly cool - so were deleted from the build.
The previous owners thought it would be a good idea to swap out the Trust turbochargers for HKS ones - for whatever reason - and not reinstall the necessary water cooling lines.
A week after I bought the car, the HKS units gave way. Overheated bearings. One suffered a collapse. Two perfectly fine turbochargers turned to scrap in very little time and miles.
Get them checked out and if the turbochargers you have fitted require the water cooling lines... get them fitted ASAP. I wouldn't risk driving it until you're sure either way.