When a member pays for a subscription to your site here on Spruz, it in turn sets their access level up to a level that is capable of seeing your paid content pages. So ultimately, the answer is yes, and you'd just need to make all current members set to the access level that you intend to use when you make your site a paying site again.
For example, by default, all members of your site start out as level one access level. You need to make sure that they are all set to level two, before you switch over to being a pay site, and then set the subscription level to 2 so that all new members signing up have to pay to become a level 2. It has to be done individually, so it's a good idea to take care of it as quickly as possible so you don't have to do it for hundreds of people all at once!
