Here is some regex that will do a similar thing in RegexPal:
(?<=(\\(?!(b|c|cp|f|fr|id\w*|jmp|periph|rem|toc\d|usfm|v|vp|x|xo)\s)\+?\w+[\s\*]|[cv]\s+\S+\s))[^\\]*?(?=\\|\Z):::\S+
Use Count (CTRL-O) to find all the words in a an entire project down to a single book.This will give you more words but it is probably more accurate. The Wordlist excludes numbers and words in certain reference fields like \r \ior and sometimes \xt which may not need to be checked for spelling, but should probably be included in a word count.
Detail
This is an explanation of the regex:
The first part is a context where you want to count words. It excludes markers as well as chapter and verse numbers: (?<=(\\(?!(b|c|cp|f|fr|id\w*|jmp|periph|rem|toc\d|usfm|v|vp|x|xo)\s)\+?\w+[\s\*]|[cv]\s+\S+\s)[^\\]*?(?=\\|\Z):::
- It includes a list of markers whose contents you probably do not want counted:
(?!(b|c|cp|f|fr|id\w*|jmp|periph|rem|toc\d|usfm|v|vp|x|xo)\s)
- This part excludes chapter numbers and verse numbers: [cv]\s+\S+\s
The second part \S+ simply finds text separated by spaces. Since it is greedy it will find text up to a space, end of string, or end of file.