I can think of two things to confirm:

The account really did get set up as SEP IRA.

There is no carry-over excess contribution being managed.

Yes it is

Don't you just love it when these problems are first noticed in the final week before October 15 deadline?

SEP's don't issue 1099's.  I hope you're not planning on taking a deduction for contributions to it. 

It was setup as a SEP IRA  many years ago - 

And there is no carry-over excess contribution

Thank you

Client just dropped off last of information Saturday  

That doesn't matter, it's all your fault anyway.  It's always the preparer's fault.  But when did he drop off this 1099?  I discourage clients from bringing me stuff piecemeal.  Generally, I don't start on a return until I have everything I need (unless the client wants to pay me two or three times the fee for doing a complete return).  They don't realize that just because they have only one preparer, doesn't mean that their preparer has only one client.  

Sometimes, though, you have to get started on the return by April 15 to figure out how much to pay with the extension request.  Is this a new client?  Was this a new SEP?

Yes 😤 and yes new client - had them bring in old returns with last of info on Saturday, when kept pressing to bring in all 1099's - brought their books in Oct 1st  ☹️- felt sorry for them as they were panicked and a friend of another client -  think they are new because probably got "fired" from last preparer -   They filed an extension somehow (I hope more than just the paperwork).  Old returns show it from prior years - they swear everything at that Management company is ALL in their SEP account - from the beginning, wondering if they have just an investment account in addition, and they think of all that money for their retirement.  Will have to call Management people tomorrow.  As they say " no good deed goes unpunished"

Sometimes we have to face reality- we all have a certain number of morons for clients.  I would be willing to bet a case of of lutefisk that your client doesn’t know what they are talking about.  I have had a number of clients over the years that don’t know if they have a retirement account or if all of their funds are are sitting in a mayonnaise jar under Funk and Wagnell’s front porch.

And some authorities don't realize the name is Wagnalls, with no apostrophe -- Mr. Wagnalls was a college classmate of Mr. Funk.  

"Wealth Management" is a generic term that I suspect is used by some boutique broker in a 100% commission arrangement with a firm that provides a minimum of supervision.  When I come across one of those I use the FINRA BrokerCheck to see what kind of record the person has.  Of course it doesn't do much good to point this out to a client, because if you can't trust your broker, who can you trust? And the individual is invariably a stellar salesperson.  

"and they think of all that money for their retirement."

Exactly.

"because if you can't trust your broker, who can you trust?"

As a previous plan administrator, I can tell you some real horror stories from trying to straighten out brokers' mistakes and outright lies to their clients.