Is it ok to switch from simlac baby formula to gurber baby formula?

Yes. In general all infant formulas have similar calorie and nutrition content. Some parents feel bad hey baby made it one formula better than another, but in general there are no problems with switching from one infant formula to another.
It's up to baby. Most infants will transition well between formulas but some do not. Though the nutrition content meets the same requirements, your kid may digest 2 products quite differently.Try to stay with similar products , soy for soy or cow for cow as a protein source protein.If your kid does not end up with digestive symptoms within a week, things will probably go well.Otherwise, modification may be neede.