Marriage records will not always indicate if one of the parties has been married before. Some marriage records may list the groom as "Mr." and the brides as "Miss" or "Mrs," but others will make absolutely no distinction.
Do not assume that if one of the parties had been married that a subsequent will make a note of it. Some records may indicate the bride is a widow, but others will not.
For this reason, unless there's a statement to the contrary, don't always conclude that the last name of the bride is her name at birth. It could very well be the last name of a previous husband.