There is no way to determine from the connection to the share itself what the platform of the server hosting the share is. The SMB protocol abstracts all of that information intentionally (this is why you can copy files to/from an NTFS share under Linux or a Mac where NTFS isn't supported).
You can glean this information anecdotally if the entire OS volume is shared (or by connecting to the C$ share -- which isn't available on non-Windows Samba servers). However, the best way to determine if the host is 64 or 32-bit is to look at the %PROCESSOR_ARCHITECTURE% environment variable on the host. The reason is because some badly-written software creates a Program Files (x86) folder or writes to a Wow6432 node in the registry even on 32-bit platforms, so their presence does not necessarily mean the platform is 64-bit.
However, all this depends on the host being available and you having the access to query it. There is no way, from a share alone on a server you don't otherwise have access to, to determine the platform of the OS hosting it if the files don't give you a hint.