Changes
I think the expr parser function was being used to strip leading zeros in the original this code was copied from Template:PMID which isn't needed in this case
{{#if:{{{1|<noinclude>$</noinclude>}}}|{{Catalog lookup link|{{{1|}}}|{{{2|}}}|{{{3|}}}|{{{4|}}}|{{{5|}}}|{{{6|}}}|{{{7|}}}|{{{8|}}}|{{{9|}}}|article-link={{#ifeq:{{yesno-no|{{{plainlink|}}}}}|yes||Employer Identification Number}}|article-name={{#ifeq:{{yesno-no|{{{plainlink|}}}}}|yes||EIN}}|link-prefix=//apps.irs.gov/app/eos/allSearch.do?ein1=|link-postfix=&names=&resultsPerPage=25&indexOfFirstRow=0&dispatchMethod=searchAll&city=&state=All+States&country=US&postDateFrom=&postDateTo=&exemptTypeCode=al&deductibility=all&sortColumn=orgName&isDescending=false&submitName=Search|list-leadout={{{leadout|}}}}}|{{error-small|Parameter error in {{tl|EIN}}: Missing [[Employer Identification Number|EIN]].}}}}<noinclude>
{{documentation}}
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</noinclude>
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