No you can't admit in any of the college without an allotment order since you have no proof that you have got seat there so that it is mandatory that you should have allotment letter to alot a seat for you in a college.Hence,Make sure that you carry one when going to alot a seat.

Hii aspirant ,

Coming to your I would like to tell you that if the college is government than you can't be admitted in the college without the seat allotment letter ,  but if the college is private then it totally depends on the college,

Hope this helps you ,

Good luck.