Yes, there’s no prohibition against the seller sending out multiple contracts to different buyers. Remember that nothing is binding for either party until a contract is fully executed, which means either party could walk away or do a deal with someone else at any point before contract execution.
Remember, this is the norm in most states such as New York where accepted offers are rather meaningless and only signed contracts have any binding effect. With that said, be careful in other states like Massachusetts where some Realtor associations will ask buyers to sign their standard offer to purchase form.
As with anything in life, anytime you sign something, you begin to put yourself in legal liability. If possible, never sign anything unless you intend for it to be a binding contract!