I'm thinking about purchasing an old Boehm-system instrument which has "Buffet, Crompton & Cie, a Paris, made in France" marked on all the parts. I believe the fingering is different and the sound is a bit 'high'. Can someone elaborate on the differences in this english horn and a modern english horn? Especially with regards to sound? If it's a bit sharp but has a rich timbre like modern English horns, then I'm planning to purchase it. It also says that it's based on the " based on the flute system". Does that mean that it has flute fingering?

Thanks for your help!

I don't know much about Boehm system fingering except that it never caught on.
As you say it is likely to play at high pitch (A = 452) which is about a quarter tone higher than A=440. It is never satisfactory to try to get these down to modern pitch as the internal tuning goes all over the place e.g if you manage to get the Gs in tune the notes above, with few fingers down will be sharp & the lower ones will be flat.

Would it be possible to use a shorter... maybe extremely short bocal to lower the entire pitch?

To lower pitch you need to use a longer bocal not shorter.
However the amount you can achieve doing this is limited. As I said in my first post this does not affect all notes equally. Just look at your oboe - the distance between the holes which vent low B & C is about twice that for the upper ones. Hence if you need to increase the length of bocal by, say, 3mm for the upper C it will need to be twice that for the low one.

Ha, I am at home because I am sick. I can't believe I made the mistake of saying shorter. Instruments are like pencils. When you're sharp, pull out. Flat, pull in.

@Contra that makes sense. What a shame.