Yes it does have a oil tank. The guy you purchased the bike from may have disconnected the oil pump making the injection oil system unless at this point. In that case the fuel would need to be premixed with oil. since he recommend the 30:1 premix of fuel and oil I would say that is how he has it set up. I like the Maxima 972 premix oil also the Maxima Super M is good also.
I use the Maxima MTL 80 wight for transmission. Yamaha's Trans Oil Plus is good also.
Look for any hoses or lines disconnected from the oil tank to the pump.
you can look for the oil line #92059 and see if bolt #92001 is connected to the intake system.
or you can fill the oil tank with oil Maxima Super M and run the bike with premixing the fuel. Then crack Bolt #92001to see if oil is being pumped to the intake system and then it would go to the cylinder.