Hidden products and web crawlers

Site URL: https://seamstofit.com

I am an SEO beginner and I am wondering if hidden products are visible to web crawlers and other search engine information gathering tools.  We are a consignment clothing store and have about 100 new products a week and rotate our sold items off of our site leaving a rolling total of about 1000 products at any one time.  We would like to keep our sold items on our site but we don't want them to show up in Squarespace's search so I guess they must be hidden.  Hence my question.  Any help or clarification will be appreciated.  

I got a response to this question from Squarespace via email.  Whether it is correct or not is up to your belief system since I don't have a way to verify it. (I am not a search engine)

That's a great question - so to clarify the information a little more which was provided by my colleague if you adjust individual products settings to hidden, it'll still be visible to search engines. With the built-in features, you can hide products from customers but this wouldn't prevent it from being crawled by Google search engines.