You may try your luck in finding Apple User Groups
in your area; as someone there may have actual 10.5
DVD (official would be Dual Layer) for the PPC version.
https://appleusergroupresources.com/find-a-group/
Online-only groups can be found here.
[The version shipped for Intel-mac would be grey-label.
And could sport 'unique part number' for the Mac itself.]
Some years ago, I sought retail 10.5 DVDs and bought some
so that every Mac I had which could upgrade past Tiger, had
the path open to do so. ~ And I found some great bargains..!
Of course you may find listing on ebay or other sites. Be wary
where the seller does not make subtle distinction between the
grey-label machine-specific system restore install media & retail.
These discussions where alternative unsupported Mac OS X installs
&/or unofficial copies of (pirated) software, were not allowed. That
had been a 'no-no' in these official Apple Support Communities.
