from the initials of the authors of the canonical textbook (The C Programming Language).

Yes. My copy sits on the shelf above my computer. It has a loose front cover, is a faded yellow color, has the ISBN number 9-130110163-3 and dates from 1978.

And on page 218/section 18.4 External definitions it give the following set of possibilities:

program:
    external-definition
    external-definition program

external definition:
    function-definition
    data-definition

function-definition:
    type-specifier(opt) function-declarator function-body

function-declarator
    declarator ( parameter-list(opt) )

parameter-list:
    identfier
    identifier , parameter-list

function-body:
    type-decl-list function-statement

function-statement:
    { declaration-list(opt) statement-list }
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I don't think you you'll find a much earlier revision than my copy, indeed I can't find any sign that it is a revised edition at all, but I can't see any interpretation of the above, that means that:

unsigned long func (c) unsigned char *c;
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was ever a legal function declaration.

There are certainly no examples in the book that look like that, though there are precious few examples of function declaration. I've been doing C a long time and I've always declared function parameters inside the parens. I well remember the old DECUS compiler used to permit some extraordinary code, which why it was so favoured by the Obfuscated-C entrants, but I still do not recall seeing people use the above declaration form.