firefox version confusion

[don vogt]

 It looks to me like I missed a sign on a turn
somewhere.
No complaint. Just asking for clarification.
 I read on Redhat the following.
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Firefox 2.0.0.5 Released

A new version of the Mozilla products (Firefox,
Seamonkey, Thunderbird) were released this week.

http://www.mozilla.org/projects/security/known-vulnerabilities.html#firefox2.0.0.5

It's rather important you ensure you've installed this
update as the browser is certainly the most abused
application these days. If you run Fedora, this update
has been available via yum for several days.
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I have been downloading firefox 2.0 and installing
manually to keep up with the latest security fixes.

When I do a "yum list firefox  I get firefox 1.5.
 I also did a "yum install firefox" and several yum
updates of firefox.
I appear to have two versions (copies?) of firefox.
 Am I wasting my time? Is the fedora build of firefox
1.5 the same as firefox 2.0? (as far as security
updates)?