From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.9) Gecko/20020408

Description of problem:
When installing with keyboard=pc104, layout=us and dead keys disabled, the right
<Alt> key doesn't work as <Alt>.  This is *extremely* inconvenient.

Version-Release number of selected component (if applicable):
XFree86-4.2.0-8

How reproducible:
Always

Steps to Reproduce:
1.Install RHL-7.3 with above keyboard settings.
2.Run "xev".
3.Press right <Alt> when xev window has focus
	

Actual Results:  xev outputs an event with "keycode 113 (keysym 0x0, NoSymbol)"

Expected Results:  there should be "Alt_R" instead of "NoSymbol"

Additional info:

I suspect that this can be caused by Alt/Meta/Win keys change since 4.0.3 (which
was used in 7.1, where everything worked fine), but I'm not so familiar with Xkb. 

Additionally, upon X start the following message appears:

The XKEYBOARD keymap compiler (xkbcomp) reports:
> Error:            No Symbols named "nodeadkeys" in the include file "us"
>                   Exiting
>                   Abandoning symbols file "default"
Errors from xkbcomp are not fatal to the X server

The keyboard InputDevice section in XFree86-4 (sans comments):
        Option  "XkbRules"      "xfree86"
        Option  "XkbModel"      "pc104"
        Option  "XkbLayout"     "us"  
        Option  "XkbVariant"    "nodeadkeys"

Of course, I have a simple solution of adding 

keycode 113 = Alt_R
add mod1 = Alt_R

to /etc/X11/Xmodmap, but that's a bit weird.