I am going to purchase a new turntable, it will have a solid hardwood plinth. It will come with  a OA2  gimbal tonearm, have a acrylic platter and a Ortofon 2M Blue cartridge. It comes with a felt mat, wondering if it would be fine to play records on just the acrylic with out the felt mat or should I use the felt mat provided
I've always put the record right on the acrylic platter when the turntable has one.
free trial with no harm done as mentioned above

decide with your own ears
I would think that layer of felt would help to reduce rumble and vibration in the table.  What other materials are mats made of?  
If you do decide to try using just the platter sans mat don't forget to adjust your VTA. Personally I'd use the mat which should help minimize micro vibrations. 
My old Rega Planar 2 with upgraded acrylic platter sounds best to my ears with record direct on the platter, no mat at all but....ymmv.