Regarding Fuji Concept single foot fly guides, are the frames the exact same shape for the Alconite (BLAG, CLAG) as they are for the SIC (TLSG)? Do they have the same "step" off of the blank?

They are roughly the same, except they are a tad lower.

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Which ones are lower?

The concept type are lower.
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But are not the SIC and the Alconite both Concept guides available in single foot fly?

If you want a higher ring from the blank in a fly guide check out the Forecast guides.

Yes they are - the SIC model LSG are concept type and are a bit lower than the standard SG or titanium TSG.

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Not trying to be difficult, but is it true that *LAG (Alconite) and *SLG (SIC) have the exact same shape and profile?

Yes.

L is the concept designation for single foot guides:
BLAG (Black single foot Alconite Guide)
LSG (Single foot SIC guide)
TLSG (titanium single foot SIC guide)

The old style has no designation, it's just SG (SIC single foot), or TSG (Titanium franed SIC single foot)

[www.visualwrap.com]

Thank you, all who responded and thank you, NERBS for providing that secret decoder ring.

No problem. Not that it matters, but that list is not current, there are a few other guide styles which I haven't bother to update:
HB; LB; LDB; TA; - probably more. At least you can understand the code now, it is REALLY confusing if you are not familiar with it.