If there is not already a service running at this port, you will have no problem. You can check with netstat -an| grep "\.3602" if one is currently up. But usually the /etc/services is just prepared with entries for well known ports.
Just for info (because it is not relevant in your case), but in some very special case, you may want to add aliases into /etc/services , this could be done entering entries this way.
infiniswitchcl 3602/tcp sapmsDSM
(i used such kind of notation once, many years ago and that was on an HP-UX system (or maybe solaris ... i'm not sure) , not sure how the other OS handle it)
... and for sure the /etc/services were initially not designed in that purpose.
There is a pre-requisite for running SAP that you need to disable a large number of ports in the /etc/services file before installing the SAP application.
I'm not sure if you, ross, meant it that way, but i would like to point out the following for clarification: the file /etc/services is just a translation device for port names to port numbers, similar to the /etc/hosts file, which translates host names to IP addresses. Its content is mostly derived from RFC1700.
Removing an entry there will in no way close or disable a certain port, just like removing an entry from /etc/hosts will not prevent communiaction with the mentioned host.
To disable communication via a certain port one will have to resort to some layer-4 filtering, i.e. firewalling: IPSec, iptables or something such.