The ones in the picture are not 33 shock absorbers.
There are 2 types for the series 3 33, the early ones have separate spring pans and the late ones have integrated spring pans. You are correct in thinking that the springs are also different, cylindrical on the earlier version, conical on the later version (top coils have a smaller diameter than the lower coils). I have a brand new boxed late type shock if you are interested? Its made by Boge and is for the left side, Boge part number 32-037-A.
Thanks for the info, and the offer! I kind of sussed they were the wrong shocks as I went an had a look at the ones on my car! Guess I was just being lazy. I noticed the noticed the ones in the pic didn't have the arm just under the spring pan that mine do.
As for the offer,the shock you have is it still available to buy? It's just is like to have em matching! And what sort of money are we talking? Pm if you wish :-)
Yes the shock is still available, box is a little battered but the shock is brand new and never fitted, slight damage to 1 of the labels but not a big issue. I'm looking for £65 for it, new price is around £100+VAT. If you need the other side the Boge part number is 32-06-A (Sachs part number is 170-477, its the same part with different labels, you will see mine has both the Boge and Sachs part numbers on it). Any decent car parts supplier should be able to obtain them but don't try an Alfa dealer as they are no longer available from Alfa Romeo.
A couple of pics of the one I have for sale (reason for sale is that I ordered some for my 16v and assumed that the part numbers were sequential between left and right but it turned out that I ordered one 16v shock and one 8v shock so I had to order another 16v one and the spare 8v one is surplus to requirements!):