Haven't tried a 59, but from my experience of the Alnico Pro 2 bridge, it can close to the Slash tone that you are looking for.
Note that GNR cds go through a lot of mixing (esp. for the guitars), it would be wiser to look up live videos of Slash on youtube and take a listen what the Alnico Pro 2 sounds like on the bridge.
The good thing of the Alnico Pro 2 bridge is that it is very versatile,and does not sound as smooth as the neck version, which is way too smooth. Sounds chimey when clean, full and punchy at high gain. Not exactly for chugga metal though, might be a little muddy at times.
Just my 2 cents..