In general yes, but a better measure of thickness specifically is it's caliper. These are usually strongly correlated with gsm for a particular type of stock, b

In general yes, but a better measure of thickness specifically is it's caliper. These are usually strongly correlated with gsm for a particular type of stock, but not necessarily for different types of stocks. For example, we use uncalendered cotton stock for our letterpress printing and which has a thicker caliper for a given weight than typical, allowing better impression when printed. Paper can be a beautiful thing when you get into it... :)