Yes, your code will only cause an internal redirect:
There is a special feature: When you prefix a substitution field with [thishost[:thisport]...] then mod_rewrite automatically strips it out. This auto-reduction on implicit external redirect URLs is a useful and important feature when used in combination with a mapping-function which generates the hostname part. Have a look at the first example in the example section below to understand this. Remember: An unconditional external redirect to your own server will not work with the prefix [thishost...] because of this feature. To achieve such a self-redirect, you have to use the R-flag (see below).