That's a hard NO !
Nothing wrong with the Millennium BXP, it's a decent bass, no question about that. Thing is Millenniums normally sell for $100 - $150, Microbass combos go for $70 - $80. A hard case is just taking up house space, unless you're travelling in a van or bus.
Play it and if you like it then offer $200 but keep $250 as your limit.
The G&L L-2000 Tribute is a fine bass , you'll be hard pressed to find another for $450.
Seeing as it's your first bass it's a tricky situation.
The G&L has a bit more going for it but you'll still need amp money and likely new strings. $200 - $250 for the Peavey leaves you plenty of scratch for strings, a comfortable strap; even a preamp pedal. The Behringer BDI-21 is just $40, don't let the price fool you; it's a very handy tool.