Does is matter in what order rules are placed in htaccess?

Well, .htaccess files use the same format as the regular Apache configuration file, so the same rules apply.

Most config settings do not depend on order, but some do - depends on the setting.

RewriteRule and RewriteCond e.g. are sensitive to order, so in that case the answer is YES.

See e.g.

http://wiki.apache.org/httpd/RewriteRule

for an explanation of the order that these are evaluated.

It does matter. Quoting from the documentation for RewriteRule:

The order in which these rules are defined is important - this is the order in which they will be applied at run-time.