[Premium-Rx] Racal 1778

[ik3glf at virgilio.it]

Hallo all,I've the chance to purchase a RACAL 1778 that I was searching since long time. I can choose from two of them, one has the AFC "disconnected" (the owner says it was done to improve the functionality of the receiver) but have a better "AM FILTER", the other does not have the "BETTER AM FILTER" but it is unmodified with the working AFC.
Does somebody out there know a reason for this modification?
I can't give you more details seen that the owner does not know which filter have been improved and how the modification have been done but, he says, it was stated on the manual. (at the moment he is not able to found the manual so he can't explain more). 
I'm quite intrigued by the "improved AM filter", but I do not know if the modified AFC is a reversible and easy modification.
Many thanks for your opinion.
NickIK3GLF